fix 6586 (#6621)

* fix 6586

* add test

* add baseline

Author: dsyme

src/fsharp/pars.fsy

@@ -132,7 +132,7 @@ let mkDefnBindings (mWhole,BindingSetPreAttrs(_,isRec,isUse,declsPreAttrs,_bindi
 let idOfPat m p = 
     match p with 
     | SynPat.Named (SynPat.Wild _,id,false,_,_) -> id 
-    | SynPat.LongIdent(LongIdentWithDots([id],_),_,_,_,_,_) -> id
+    | SynPat.LongIdent(LongIdentWithDots([id],_),_,None, SynConstructorArgs.Pats [], None,_) -> id
     | _ -> raiseParseErrorAt m (FSComp.SR.parsIntegerForLoopRequiresSimpleIdentifier())
 
 let checkForMultipleAugmentations m a1 a2 = 

tests/fsharp/typecheck/sigs/neg115.bsl

@@ -1,2 +1,2 @@
 
-neg115.fs(8,30,8,34): typecheck error FS0001: Expecting a type supporting the operator 'get_Item1' but given a tuple type
+neg115.fs(6,9,6,17): parse error FS0525: An integer for loop must use a simple identifier

tests/fsharp/typecheck/sigs/neg115.fs

@@ -1,9 +1,8 @@
 
 module M
 
-    let inline test (arg: ^T when ^T : struct) = 
-        (^T : (member Item1: _) (arg))
+    let foo x = x
 
-    let f () =
-        let a = test struct (1, 2)
-        ()
+    for i foo 12 = 1 to 20 do 
+        printfn "%d" i
+